Embodiments described herein relate to fuel injectors for engines of vehicles. More specifically, embodiments described herein relate to nozzles for fuel injectors of vehicle engines.
The conventional combustion process in a diesel engine is initiated by the injection of fuel into a combustion chamber containing compressed air. The fuel is directly injected into the combustion chamber by a fuel injector having a perforated nozzle tip extending into the combustion chamber. The nozzle tip may extend slightly into the combustion chamber from a wall of the chamber. Typically, the nozzle tip is located opposite a reciprocating piston of the combustion chamber. The nozzle tip has a plurality of orifices from which fuel is extruded into the combustion chamber.
Fuel injectors break up a stream of injected fuel into small liquid particles that are suitable for rapid and complete combustion, called fuel atomization. The diesel fuel is typically injected at high pressures out through the plurality of orifice holes that are located at the nozzle tip. The resultant spray pattern is separate and distinct plumes of atomized fuel droplets. The fuel droplets evaporate and mix with the combustion air for a given temperature, pressure and air/fuel ratio.
To operate the nozzle, pressure from the delivery of fuel from the injector acts upon a valve until a spring preload on the valve is overcome. The valve rapidly opens and fuel is sprayed from the nozzle tip until the pressure falls and the spring loading returns the valve to its seating.
Thus, the fuel injector nozzle must deliver the fuel at a sufficiently high injection pressure to the combustion chamber for atomization. Generally, the higher the injection pressure, the greater the improvement in fuel economy and the greater the reduction in emissions. Conventional injector nozzles may fail when they are unable to withstand the high pressures built up within the nozzle, which is required for fuel delivery under high pressure. Currently, the conventional nozzle pressures are limited to a maximum of about 2500 bar before failure of the nozzle can occur.